Drug delivery device

Abstract

A drug delivery device having a housing containing a gas generator controlled by an electronic controller. The gas generator generates gas into a reciprocable chamber, whereby reciprocation of the chamber causes a lever to reciprocate a pawl, and this action causes a ratchet to undergo incremental advancement. The device may also be provided with manual control for delivering a bolus dose of drug when necessary.

What is claimed is: 
     
       1. A wearable drug delivery device, comprising:
 a housing with an adherent patient surface for placing on a patient, and a reservoir disposed within the housing; 
 a cannula in fluid communication with the reservoir and movable relative to the patient surface between a retracted position within the housing and an exposed position in which at least a portion of the cannula extends through the patient surface outside of the housing; 
 a piston slidably supported within the reservoir and operable to expel a drug from the reservoir; 
 a first drive member movably disposed within the housing and having a first portion; and 
 a second drive member at least partially disposed within the reservoir and having a second portion that is slidingly engageable with the first portion of the first drive member; 
 wherein the first and second drive members cooperate to slidably displace the piston in a first linear direction to expel a drug from the reservoir; and 
 wherein the first drive member engages the second drive member to prevent the piston from moving in a second direction opposite to the first linear direction. 
 
     
     
       2. The device according to  claim 1 , wherein the second drive member has an irregular surface defined by a series of peaks and troughs along the first linear direction. 
     
     
       3. The device according to  claim 2 , wherein the first drive member continuously engages the irregular surface of the second drive member. 
     
     
       4. The device according to  claim 2 , wherein the first drive member slidably engages the irregular surface of the second drive member. 
     
     
       5. The device according to  claim 1 , wherein the first drive member is slidable relative to the second drive member for expelling a drug from the reservoir. 
     
     
       6. The device according to  claim 1 , wherein the cannula is retractable into the housing subsequent to the expelling of a drug from the reservoir. 
     
     
       7. The device according to  claim 1 , wherein the entire first member is rotatably moveable relative to the reservoir and the patient surface. 
     
     
       8. The device according to  claim 1 , wherein the first drive member comprises a reciprocable lever. 
     
     
       9. The device according to  claim 1 , wherein the reservoir comprises a prefilled cartridge. 
     
     
       10. The device according to  claim 1 , further comprising a controller to effect rotational movement of the first drive member. 
     
     
       11. A method of manufacturing a wearable drug delivery device, comprising:
 providing a housing having a reservoir disposed therein, the reservoir having a piston slidably supported therein that is operable to expel a drug from the reservoir; 
 providing an adherent patient surface on the housing for adhering the device to the patient; 
 providing a movable a cannula in the housing, the cannula being movable from a retracted position within the housing to an exposed position in which at least a portion of the cannula extends through the patient surface outside of the housing; 
 fluidly connecting the cannula to the reservoir; 
 providing a first drive member to be displaceable within the housing, the first drive member having a first portion; 
 providing a second drive member at least partially within the reservoir, the second drive member having a second portion that is slidingly engageable with the first portion of the first drive member; 
 wherein providing the first and second drive members comprises: 
 
       operatively connecting the first and second drive members to cooperate to slidably displace a piston in the reservoir in a first linear direction to expel a drug from the reservoir; and
 engaging the first drive member with the second drive member to prevent the piston from moving in a second linear direction opposite to the first linear direction. 
 
     
     
       12. The method according to  claim 11 , wherein the second portion of the second drive member comprises an irregular surface defined by a series of peaks and troughs along the first linear direction; and
 wherein the first portion of the first drive member slidably engages the irregular surface of the second drive member. 
 
     
     
       13. The method according to  claim 11 , wherein the reservoir comprises a prefilled cartridge, and the method further comprises prefilling the cartridge and subsequently placing the prefilled cartridge into the housing. 
     
     
       14. The method according to  claim 11 , further comprising providing a gas generator and a return spring in the housing to rotatably move the first drive member.